Electric lamp annunciator indicating assembly



w. c. ARRAsMlTl-l 3,007,150

ELECTRIC LAMP ANNUNCIATOR INDICATING ASSEMBLY 2 Sheets-Sheet 1 Oct. 3l,1961 Original Filed Oct. 22, 1956 Oct. 31, 1961 w. c. ARRASMITH3,007,150

ELECTRIC LAMP ANNUNCIATOR INDICATING ASSEMBLY Original Filed Oct. 22,1956 2 Sheets-Sheet 2 nite :1;

l@ Claims. (Ci, 34h-38E) The present invention relates to electricalannunciator alarm systems and the like. This application is a divisionof copending application Ser. No. 617,618, filed October 22, 1956, andnow United States Patent 2,934,752 of April 26, i960, entitled WarningSystem and Apparatus.

The invention is more particularly directed to an improved apparatus andsystem for indicating at a central panel the existence of hazardous orotherwise undesired conditions at any of a plurality of mutually spacedremote points.

The apparatus and system of the invention are especially applicable foruse in aircraft and, for that reason, will be described in such anenvironment. However, it will be evident as the description proceedsthat the invention is susceptible to -other applications. In fact, thesystem to be described is generally useful whenever it is desired toindicate a remote hazardous condition at a central station.

Annunciator warning systems in general are well known. An emcient systemof this type is disclosed and claimed, for example, in copendingapplication Ser. No. 505,305, which was filed March 2, 1955 in the nameof the present inventor, and which is assigned to the assignee of thepresent application, and which has now issued as United States Patent2,887,677 on May 19, 1959.

Annunciator warning systems usually contain a series of annunciatorlamps positioned on a central control board and individually connectedto respective sensing elements. The sensing elements are located atvarious positions whose individual conditions are to be monitored at thecentral station. Each of these sensing elements is usually adapted toclose a pair of electrical contacts whenever a hazardous conditionarises at its particular position.

Each of the annunciator lamps is usually positioned behind a translucentpanel bearing inscriptions identifying the particular hazardouscondition represented by that lamp. Then, when a sensing element closesits contacts, the corresponding annunciator lamp is illuminated to lightup the panel and cause the inscriptions on the panel to become visible.These inscriptions, for example, may read Fuel Level Low, Generator Out,Hatch Unsafe, and so on.

ylt is also usual in annunciator warning systems to incorporate a masterwarning instrument. This latter instrument is actuated simultaneouslywith the actuation of an annunciator lamp when any of the sensingelements close to indicate that a hazardous condition has occurred. Themaster warning instrument may include a relatively bright lamp or abuzzer, and its purpose is to draw the operators attention to the factthat a hazardous condition has arisen. The operator then determines fromthe annunciators the nature of this hazardous condition, as indicated bythe inscriptions on the translucent annunciator panel that has becomeilluminated. An acknowledgement or re-set switch is usually provided inthe master warning instrument which enables the operator to deenergizethe lamp or buzzer after it has served its purpose.

Even after the master warning instrument has been deenergized by theoperator actuating the re-set switch, the illuminated annunciator panelcontinues to be so illuminated until the faulty or hazardous conditionhas been dli aaa-:atea oat. si, rsa1 corrected. Moreover, thedeenergized master Warning instrument is ready to be energized again, ifand when another hazardous condition arises at another point and eventhough the first condition has not been cleared.

Also included in the apparatus and system of the general annunciatorwarning type are certain ancillary controls such as a manual dimmingswitch for dimming the annunciator panels and the master warning lampwhen so desired. The systems usually also include certain test controlsfor determining whether their various components are operating7properly.

As noted above, annunciator alarm systems nd perhaps their greatestutility in aircraft. However, it is a well known fact that space is at apremium in modern aircraft. Therefore, it is essential that the physicalsize of the apparatus for the alarm system be reduced as much aspossible. lt is also important, however, that the cornponents of theapparatus be readily accessible for servicing and for the replacement oflamps and other consumable parts.

The apparatus of the present invention is designed and constructed toutilize miniature diodes for isolating purposes in place of controlrelays, such relays having been considered essential in prior artequipment for use in annunciator alarm systems. By devising improvedcircuits, which will be described in detail and which incorporate suchdiodes, the apparatus of the invention is capable of performing all therequired control and alarm functions described above. Moreover, theapparatus of the invention performs these functions at a material savingin necessary components and with a material reduction in spacerequirements, as compared with prior art units of this general type.

In accordance with the invention, and contrary to prior art practice,the control circuit associated with each sensing element of the systemis incorporated in la small capsule and the associated annunciator paneland lamp (or pair of lamps) are adapted to plug into the front wall ofthe capsule. These capsules are designed and constructed in a manner tobe described so that they can be conveniently stacked, one over theother, in a rigid assembled unit. This provides exibility and enablesdifferent numbers of capsules corresponding to the nurnber of points tobe monitored conveniently to be used in different installations.

The electric lwiring and circuits of the various capsules are simple andstandardized. For example, in the embodiment of the invention to bedescribed, the capsules are all connected in parallel across the leadsof a 5-wire cable which extends to the various controls of the system.The only other connection to each of the capsules is a single lead fromit to its associated sensing element.

The apparatus of the invention, moreover, is constructed so that each ofthe individual capsules may be easily removed and replaced as a unitshould any capsule become defective. Also, the individual annunciatorpanels and lamps are movable as a unit to permit simple replacement ofthe annunciator lamps as they burn out. A unique indexing arrangement isused to assure that the panels will always be returned to their propercapsules. This, of course, is to prevent the inscriptions on aparticular panel from erroneously designating which particular hazardouscondition has actually occurred.

Other features and advantages of the invention will become apparent fromthe following description, particularly when taken in conjunction withthe accompany drawings in which:

FGURE l is a rear perspective view of a plurality of annunciatorcapsules and their associated panel-andlamp units, these capsules beingstacked and assembled in accordance with the present invention, thisView also indicating the electrical connections to the various capsules;

FIGURE 2 is a front view of the assembly of FIGURE 1 showingparticularly a series of translucent panels individually associated withthe capsules, the panels containing different inscriptions correspondingto respective hazardous conditions to be indicated by the illuminationof their respective annunciator lamps;

FIGURE 3 is a perspective view of an annunciator capsule constructed inaccordance with the invention and of its associated translucent panelportion, and this figure shows particularly a mechanical indexing unitwhich serves to assure that the translucent panel associated with thecapsule will not inadvertently be mounted on another capsule which wouldresult in an erroneous indication;

FIGURE 4 is a circuit diagram of the controls of the system and of theelectrical connections in the annunciator capsules, and showingparticularly an improved circuit perrnitting the use of diodes to effectthe necessary inter-circuit isolation which was previously provided forby the use of relays and the like;

FIGURE 5 is a sectional view illustrating the mechanical details of themaster warning instrument of the system and of the mechanical re-setswitch also included in the unit; and

FIGURE 6 is a perspective view of the master warning instrument.

As stated previously, in the system of the invention and contrary toprior art practice, the control circuit for each annunciator lamp isindividually housed in a capsule, and an associated translucentannunciator paneland-lamp unit is plugged into the capsule. A stack ofsuch capsules is indicated at 10 in FIGURE l, and the capsules aremounted on the rear side of a panel 12 by appropriate mounting screws,not shown. The capsules are held in their stacked condition by a pair ofscrews 14 and 16 which extend through the stack.

A suitable opening in the panel 12 exposes the front edge of each of thecapsules 10. A translucent panel 22 having a pair of annunciatorindicator lamp plug-andsocket assemblies embedded in its interior isassociated with each of the capsules 10. These translucent panels areconveniently numbered, as shown in FIGURE 1.

The plug-and-socket assemblies embedded in the translucent panel 22 areindicated in FIGURE l at 24 and 26. The annunciator lamps are supportedin these assemblies in known manner, and the assemblies form respectivebayonet type plugs. These plugs are received by appropriate aperturesand by mating electrical sockets positioned in the front of theassociated capsule 1). The bayonet type plug portions of theplug-and-socket assemblies serve not only to establish electricalcontact to the lamps supported in the socket portions, but they alsoserve to support the translucent panel on its associated capsule.

As shown in FIGURE 2, the front face of each of the translucent panels22 is appropriately inscribed to represent a particular hazardouscondition. Whenever a pair of annunciator lamps is energized, thecorresponding translucent panel glows to indicate the location of thehazardous condition that has arisen.

Each of the capsules 10 has, in the illustrated embodiment, a set oftive electrical terminals 28a, 28h, 2SC, 28d and 28e, mounted on itsrear edge. These terminals are preferably located so that equivalentterminals of each capsule are disposed in vertical alignment when thecapsules are stacked, as shown in FIGURE 1. This enables the terminalsof all the stacked capsules to be conveniently connected in theillustrated manner across a fivewire cable 30. This cable provides allthe connections to the controls of the system and to the master warninginstrument.

Each of the capsules 10 has a further electrical terminal 32 mounted onits rear edge, and this latter terminal is connected by an individualconnection to the sensing element associated with that particularcapsule, and which sensing element is located at one of the areas to bemonitored.

It is evident that the apparatus shown in FIGURES 1 and 2 is mostconvenient to install. Moreover, the equipment is extremely flexiblesince it is merely necessary to stack a particular number ofstandardized capsules to adapt the assembly for any particularinstallation. When the desired number of capsules corresponding to thenumber of areas to be monitored is determined, they are stacked and heldat a rigid unit by the screws 14 and 16. Then, it is merely necessary torun the cable 30 up the back of the capsule stack and to make theappropriate illustrated connections to the terminals 28a- 28e. Also, asingle lead is connected from each of the additional terminals 32 to therespective sensing elements at the various areas to be monitored.

The translucent panel assemblies 22 are individually plugged into theircorresponding capsules from the front of the supporting panel 12 andthrough the opening in the supporting panel. The inscribed front facesof the translucent panels constitute a display which is illustrated inFIGURE 2.

It is evident, that from time to time it will be necessary to remove oneor more of the translucent panels 22 as its lamps become burned out. Itis also evident that it is most important for the removed panel to bereturned to its proper capsule, otherwise, it will not tally with thearea monitored by that particular capsule. This proper replacement ofthe translucent panels is facilitated by numbering them in the mannershown in FIGURE l. However, in order to provide a foolproof system,indexing system is used. rl`his indexing system renders it impossible toreturn a translucent panel to its wrong capsule.

The indexing system is more clearly shown in FIF- URE 3. As clearlyshown therein, each capsule 10 has a pair of electrical sockets 34 and36 mounted adjacent its front edge. As previously described, thesesockets receive the bayonet plug portions of the plug-and-socketassemblies 24 and 26 associated with the corresponding panel 22. Aspointed out, the sockets 34 and 36 serve, not only to establishelectrical contact to the annunciator lamps in the correspondingplug-and-socket assemblies 24 and 26, but also to support thecorresponding translucent panel 22.

As is shown in FIGURE 3, a pair of annunciator lamps 38 and 40 arerespectively supported in plug-and-socket assemblies 24 and 26, andthese lamps extend into the interior of the translucent panel 22 tolight up the panel when they are energized. Whenever it is desired toreplace a lamp, the panel 22 is pulled outwardly to remove theassemblies 24 and 25 from the sockets 34 and 36. The defective lamp maythen be replaced by a new one.

The actual constructional details of the electrical sockets 34 and 36,and of the plug-and-socket assemblies 24 and 26 are in themselves wellknown, and a detailed showing and description of these units is believedto be unnecessary.

To assure that a removed translucent panel 22 will be plugged back intoits proper capsule 1t), a spade screw 42 (or similar element) is screwedinto the front edge of each capsule 10 and a corresponding spade screw44 is screwed into the rear edge of its associated panel 22. These spadescrews, as shown, have heads that are attened in a plane traversed bytheir axis of rotation. The screws are so supported by each capsule 10and by each panel 22 that associated ones are displaced slightly fromone another when the translucent panels art plugged into place. The headof the spade screw 42 on a particular capsule 10 is given a selectedinclination or angular orientation, and the head of the spade screw 44on its corresponding translucent panel is given a mating inclination, orangular orientation.

In the staclt of FIGURE l, for example, each of the l capsules lil has aspade screw, or similar element, screwed to its front edge, such as thespade screw 42. The head of each such screw on the various capsules isgiven' a slightly different inclination or langular orientation, and, ineach instance a spade screw (or similar element) is screwed into the-facing edges of each of the associated translucent panels 22. Thelatter spade screws in each instance are mounted so that their headswill have a mating angular orientation with corresponding ones of theheads of the spade screws on the capsules. Then, the insertion of atranslucent panel 22 in any one of the capsules other than its propercapsule is prevented because its spade screw will engagethe spade screwon the front edge of the capsule. However, when a translucent panel 22is inserted into its proper capsule, the heads of the spade screws 42and 44 do not er1-gage and the panel may be plugged into place. Thesespade screws also prevent a panel 22 from being inadvertently pluggedupside down into its capsule.

The electric control system incorporated in each of the capsules lo andconnecting the capsules to the various controls of the system is yshownin FIGURE 4. Since the circuits in the capsules are identical, one onlywill be described.

The terminals 28a, 2gb, 2SC, 28d and 28e of FIG- URB 1 are shown inFlGURE 4, and the terminal 32 is also shown. Each capsule contains asingle relay having an energizing winding Sil and having a pair ofmovable contact arms 52 and 54. When the winding 5t) is energized, thearm 52 opens its upper contact and closes on its inactive lower contact.At the same time, when the winding 50 is energized, the arm 54 opensfrom its inactive lower contact and closes on its upper contact.

One terminal of the winding Sti is connected to the terminal 32 and theother terminal of this winding is connected to the cathode of a diode56. The anode of this diode is connected to the terminal ZSC.

The term diode will be used inV a generic sense in the subsequentdescription to refer to any unilateral or asymmetrical conductivedevice. The diodes actually used in a constructed embodiment of theinvention were asymmetrically conductive crystals of well known type.

The upper contact associated with the movable arm 54 is connected to thecommon junction of the diode S6 and the winding Sti. The movable arm 54,itself, is connected to the terminal Z811. The movable arm 52 isconnected to the common junction of the winding Sli andthe termina-l 32.The upper contact associated with this arm is connected to the cathodeof a diode 6d. The anode of this diode is connected to the terminal 28a.

The two annunciator lamps 33 and 40 which, as previously described, aremounted in the translucent panel portion off-the unit, are connected inparallel, as shown in FiGURE l4. These parallel connected lamps areconnected through their sockets to the common junction of the winding 56and the terminal 32 and to one terminal of a resistor 62. The otherterminal of the resistor 62 is connected to the terminal 28h.

A diode `ed has its cathode connected to the cornmon junction of thelamps 3d, du and the resistor 62, and the anode of this diode isconnected to the terminal 28d. A diode 66 has its cathode connected tothe terminal 28e, and the anode of this diode is connected to theterminal 32.

The elements and circuitry described above constitute the internalconnections and the components of each of the capsules 10. In theillustrated embodiment of the invention, therefore, each capsulecontains only a relay (which is of the miniature type and well known tothe art) a resistor' and four diodes.

The tive leads of the ca-ble di! of FIGURE l are represented by theleads 68, 7i), 72, '74 and 76 respectively, in FIGURE 4. It will be seenthat each of these leads d is connected to a corresponding one of theterminals 28a-28e of each of the capsules it);

The lead '613 is connected to the positive terminal of a source 78 ofdirect voltage, the negative terminal of this source being grounded. Thelead 'l'tl is connected to the yiixed contact of a test switch titl.This switch may be in the form of a single-pole-single-throw Inanuallyoperated push button switch. The movable arm of the switch is normallybiased out of engagement with the hxed Contact, and the movable arrn isgrounded.

The lead i2 is connected to the flixed contact of a dimmer switch S2.This latter switch may also be in the form of asingle-pole-single-tlrr-ow manually operated push button switch. Themovable arm of the switch 82 is connected to the positive terminal ofthe source 78. The movable arm of the switch 82 is normally biased intoengagement with its fixed contact and when the movable arrn isdepressed, the connection from the positive source to the lead 72 isbroken.

The lead 712- is connected to a terminal 34 of a master warninginstrument 36 which will be described. The terminal Se is connected toone side of a pair of parallel connected master `warning lamps 85 and9i). A resistor 92 connects the other side of these parallel connectedlamps to a terminal 94 of the unit. A further terminal 96 is connectedto the anode of a diode 98, and the cathode of this diode is connectedto the common junction ot the lamps 38, 98 and the resistor 92. Theterminal 96 is connected external-ly to the lead 72;.

The unit Se also includes an acknowledge or reset switch lili?. Themechanical details of this switch will be described. The switch isnormally spring-biased to an open condition and its is asingle-pole-single-throw type. The iixed Contact of the switch iti@ isconnected to a terminal 62 of the unit do which, in turn, is connectedto the positive terminal of the source 78. The movable arm of the switchiti@ is connected to a terminal 3.94 of the instrument 86, and thisterminal is connected externally to the lead 76. The terminal 9d of theinstrument is connected externally to the positive terminal of thesource 78.

The terminal 32 is connected to the movable arm of a switch liloincorporated in a sensing element at the area to be monitored. Thisswitch is actuated in known manner to close in response to theoccurrence of a certain condition. The switch includes a fixed Contactwhich is grounded, and the movable arm of the switch closes with thatfixed contact upon the occurrence of a certain condition as, forexample, the rise of pressure or temperature above a selected threshold,a drop in oil pressure, the mechanical shifting of an element, etc.

Sensing elements, in themselves, are well known to the art. It isbelieved, therefore, that a detailed description of such an element isnot necessary to the completeness of the present specification.

Assume now that the hazardous condition monitored by the sensing elementNo. 1 has occurred, thereby causing the movable arm of the switch liloin that element to `close on its grounded fixed contact. rIhre closureof the switch ldd places a ground on the terminal 32 of the capsule li?.This completes a circuit from the vnegative terminal of the source 78through the annunciator lamps 33 and du', through the diode 64, andthrough the switch S2 to the positive terminal of the .source 7S. Theannunciator lamps 3S and dit, therefore, glow brightly to licht up theinscriptions on their `associated translucent panel 22.

The closure of the switch ltirs in the sensing element No. l alsocompletes -a circuit from the negative terminal of the source 7g throughthe terminal 32, through the movable arm 52 of the relay and its uppercontact, down through the diode du, through the master warning lamps S8and 9d, through the diode 98, and through the dimmer switch $2 to thepositive terminal of the source 73. The lamps 3% and tl of the masterwarning instrument, therefore, also glow brightly.

It should be pointed out that the master warning instrument is usuallylocated in such a position that it may readily catch the eye of theoperator to appraise him of the fact that something is wrong. Theoperator then turns to the annunciator panels to determine the localityof the fault of hazardous condition.

When the operators attention has been attracted by the glowing lamps inthe master warning instrument, the instrument has served its purpose.Now, the master warning lamps can be deenergized and placed in readinessto indicate another monitored hazardous condition that might arise. This`deenergizing of the master warning lamps is accomplished by closing thereset switch 100.

When the reset switch 100 is closed, the lead 76 connects the terminal2SC of the capsule to the positive terminal of the source 78. Thiscauses the relay winding 50 to be energized to move the arm 54 to itsupper contact. The arm 54 now establishes a circuit which holds thewinding 50 energized so long as the fault at the No. 1 sensing elementcauses the switch 106 to remain closed. At the same time, the energizingof the relay winding 50 causes the arm 52 to move from its upper contactto break the connection to the lamps S55 and 90 in the master warninginstrument. The master warning lamps, therefore, are deenergized.However, the annunciator lamps 38 and 40 remain energized and theircorresponding inscribed translucent panel continues to glow as long asthe fault continues.

The dimmer switch 82 serves as a means for dimming the annunciator lampsand the master warning lamps when so desired. When the dimmer switch isdepressed, the circuit through the diode 64 from the annunciator lampsis broken, and an auxiliary circuit through the resistor 62 and throughthe terminal 2811 to the positive terminal of the source '78 isestablished. The annunciator lamps, therefore, continue to glow but withreduced luminance because the resistor 62 has effectively been placed intheir energizing circuit. Likewise, the actuation of the dimmer switch82 breaks the circuit from the master warning lamps 88 and 90 throughthe diode 98, and causes these lamps to be energized through theterminal 94 and through the resistor 92. The master warning lamps,therefore, also continue to glow but also with reduced brilliance.

The test switch 80 is effectively connected through the diode 66 inshunt across the sensing elements. Whenever this test switch isactuated, it simulates the closure of all the sensing elements so thatappropriate tests can be made to assure that the system is in properworking order.

The diode 60 in each of the capsule circuits functions as aninter-circuit isolation means to prevent the closure of one of thesensing elements, and the resulting energizing of the lamps 88 and 90 inthe master warning instrument, from energizing the annunciator lampsassociated with deactivated sensing elements. That is, this diode 60enables a common master warning circuit to be connected to a pluralityof independent annunciator circuits without causing interaction betweenthe latter circuits.

The diode 64, in like manner, functions as an isolation means andpermits a common `dimmer circuit to be connected to the plurality ofindependent annunciator circuits without producing interaction betweenthe annunciator circuits when the dimmer switch is open.

In like manner, the isolation diode 56 in each of the capsules permits asingle reset switch 100 to be used to control all the capsule unitswithout producing interaction between the independent annuciator lampcircuits when this switch is open. The isolation diode 66 in like mannerprevents interaction between the annunciator circuits due to the singlecircuit to the test switch S0.

Therefore, the disclosed circuits which utilize isolation diodes and asingle relay are capable of providing all the controls and indicationsof the more complicated and space consuming prior art systems. Unlikethe prior art circuits of this general type, the desired isolation isobtained by means of simple diodes rather than by relays.

These diodes use less space than the relays, and they are a materialfactor contributing to the resulting minimum space requirements of theimproved apparatus of the present invention.

One embodiment of the master warning instrument 86 is shown in FIGURES 5and 6, and as shown in these figures, the instrument may be convenientlyhoused in a casing 102. The switch is mounted on the back wall of thecasing and, as previously indicated, may be a single-pole-single-throwpush button type. A strip 104 which may, for example, be composed of asuitable plastic is resiliently supported in the casing by means of apair of screws 106 and 108. These screws extend forwardly from the backof the casing and through a strip 104 at the opposite ends of the strip.

A pair of coil springs 110 and 112 are respectively supported by thescrews 106 and 108, and these springs serve resiliently to hold thestrip 104 in spaced relation with the back of the casing 102. The strip104 extends across the actuating button of the switch 100, and thearrangement is such that whenever the strip is depressed against thebias of the springs 110 and 112, it moves against the actuating buttonand the switch 100 is actuated.

The master warning lamps S8 and 90 are supported in appropriate sockets114 and 116 on the strip 104. A pair of open cylindrical members 118 and120 is mounted on the strip 104 in respective coaxial relation with thesockets 114 and 116.

The instrument has a cover composed of a translucent panel 122 having aplastic body portion 124 which is adapted to be inserted through anopening in Ithe front of the casing 102. A pair of cylindrical members126 and 128 is embedded in the body portion 124 of the cover inrespective axial alignment with the cylindrical members 113 and 120.When the panel portion 122 and the body portion 124 of the cover areinserted in the opening in the casing 102, the cylindrical members 126and 128 are adapted to engage the members 118 and 120 respectively inclose lit. The lamps, therefore, extend into the cylindrical members 126and 12S, and these cylindrical members are open ended so that the lampsmay glow through the panel 122 which is composed of suitable translucentmaterial.

In normal operation, and when the master warning instrument isenergized, the lamps 88 and 90 glow brilliantly through the front panel122. When it is desired to deenergize these lamps, it is merelynecessary to move the front panel inwardly so that the strip 104actuates the switch 100. This actuation of the switch causes the masterwarning lamps to be deenergized in the described manner. The force fromthe panel 122 is transmitted to the strip 104 by the frictionalengagement of the cylindrical members 126, 12S and the cylindricalmembers 11S and 120.

As previously pointed out, the master warning instru ment is mounted ina position where it can readily attract the attention of the operator.When his attention has been so attracted, the operator need merely movehis hand against the panel 122 of the instrument and press it inwardlyto deenergize the lamps 88 and 90.

The invention provides, therefore, an improved and simplifiedannunciator apparatus and system. In accordance with the invention, thecircuits associated with the individual annunciator lamps are simplifiedand miniaturized in such a manner that they can be convenientlyencapsulated. The individual capsules can be filled with a suitableplastic to pot the components and circuitry therein.

Further in accordance with the invention the translucent annunciatorpanels are constructed to plug into their associated capsules instead ofbeing formed as a separate and remote unit.

A simple and improved indexing system is provided to assure that eachannunciator will be plugged into its sperano proper capsule. Thisindexing system also assures that the translucent annunciator panelsWill be plugged in right-sideup.

The apparatus of the invention is extremely simple to install and toconnect. Moreover, it is extremely flexible, and as many standardizedcapsules and associated annunciator panels can be used as there arelocations to be monitored.

l claim:

1. An electric lamp annunciator indicating assembly including: a capsulemember containing electrical components and circuitry for producing anenergizing current in response to the happening of a monitoredcondition, a removable lamp housing member having an indicating face,releasable plug and socket means respectively mounted on said capsulemember and on said removable lamp housing member and having acontiguration to removably support said removable lamp housing member onsaid capsule member, an electric socket means mounted in one of saidmembers and adapted to be connected to circuitry in said capsule memberfor holding at least one electric annunciator lamp in position to glowthrough the indicating face of said removable lamp housing member whensaid removable lamp housing member is held in place on the capsulemember by said plug and socket means and upon the happening of themonitored condition.

2.. The electric lamp annunciator indicating assembly defined in claim land which includes a rst indexing member mounted on the front edge ofsaid capsule member having a flat portion extending essentiallyperpendicularly to the plane of said front edge and at a predeterminedangular orientation, and a second indexing membei' mounted on saidremovable lamp housing member having a ilat portion extending esentiallypeipendicularly to the plane of the rear face of said housing member atan angular orientation such that the at planar portion of said secondindexing member is spaced and essentially parallel to the at portion or"said iirst indexing member when sai-d lamp housing member is in place onsaid front edge of said capsule member.

3. An electric lamp annunciator indicating assembly including: a capsulemember having a front edge and containing electrical components andcircuitry for producing an energizing current in response to thehappening of a monitored condition, a removable lamp housing memberhaving an indicating face, iirst electric socket means supported in saidremovable lamp housing member for holding at least one electricannunciator lamp in a position to glow through the indicating face ofsaid removable member, and releasable electric plug and socket meansrespectively mounted on said front edge of said capsule member and onsaid removable lamp housing member and connected to circuitry in saidcapsule member and to said first electric socket means and ha ing aconfiguration to removably support the removable lamp housing member onsaid front edge of said capsule member and to establish electric contactto said iirst electric socket means from the electric circuitry in saidcapsule member.

4. An electric lamp annunciator indicating assembly including: a capsulemember having a front edge and containing electric components andcircuitry for producing an energizing current in response to thehappening of a monitored condition, iirst electric socket means mountedon the front edge of said capsule member and connected to the circuitrytherein, a removable translucent lamp housing member having a front facewith a particular inscription formed thereon and having a rear face,further electric socket means supported in said translucent lamp housingmember for holding at least one electric annunciator lamp in a positionto glow through the front face thereof, and electric plug meanselectrically connected to said further electric socket means in saidtranslucent member and protruding from the rear face of said transi@lucent member, said electric plug means having a coniiguration to beengaged by said first electric socket means on said capsule member so asto removably support said translucent lamp housing member on saidcapsule member and to establish electric contact to said furtherelectric socket means from the electric circuitry in said capsulemember, t

5. An electric lamp annunciator indicating assembly including: acapsule-like housing having a front edge and containing electriccomponents and circuitry for producing an energizing current in responseto the happening of a monitored condition, a iirst pair of electricsockets mounted in spaced relationship on said front edge of saidcapsule-like housing and connected to the circuitry therein, anelongated translucent lamp housing having a front face with particularinscriptions formed thereon and having a rear face, a second pair ofelec-tric sockets supported in said translucent lamp housing in spacedrelationship for holding a pair of electric annunciator lamps in thetranslucent lamp housing in a position to glow through said front facethereof, and a pair of electric plugs respectively connected torespective ones of said second pair of sockets in said translucent lamphousing and protruding out from the rear face of said translucent lamphousing, said pair of electric plugs each having a coniigura-tion andpositioned to be respectively engaged by respective ones of said firstpair of electric sockets on said forni edge of said capsule-like housingso as to removably hold said translucent lamp housing on said front edgeof said capsule-like housing and to establish electric contact from saidelectric -circuitry in said capsulelike housing to said second pair ofelectric sockets in said translucent lamp housing.

6l An electric lamp annunciator indicating assembly including: acapsule-like housing a front edge and containing electric components andcircuitry for producing an energizing current in respons-e to thehappening of `a monitored condition, rst electric socket means mountedon said front edge of said housing and connected to the circuitrytherein, a removable translucent lamp housing having a front face with aparticular inscription formed thereon and having a rear face, secondelectric socket means supported in said translucent lamp housing forholding at least one electric annunciator lamp in saidtranslucent lamphousing in a position to glow through the front face thereof, electricplug means connected to said second electric socket means in saidtranslucent lamp housing and protruding out from the rear face of saidtranslucent lamp housing, said plug means having a configuration to beengaged by said iirst electric socket means on said front edge of saidcapsuledike housing to establish electric contact yfrom the electriccircuitry in said capsule-like housing to said second electric socketmeans in said translucent lamp housing, `a iirst indexing membersupported on said front edge of said capsulelike housing having a flatplanar portion extending essentially perpendicularly to the plane ofsaid front edge of said capsule-like housing at a predetermined angularorientation, and a second indexing member supported on the rear face ofsaid translucent lamp housing having a ilat planar portion extendingessentially perpendicularly to the rear face of said translucent `lamphousing member at an angular orientation such that the at planar portionof said second indexing member is spaced and essentially parallel to theflat planar portion of said first indexing member when said translucentmember is in place on said front edge of said capsule-like housing bythe engagement of said first electric socket means with said plug means.

7. An electric lamp annunciator indicating assembly including: a firsthousing member containing electrical components including an electricswitch and further including circuitry for producing an energizingcurrent in response to the happening of a monitored condition, a movablestrip member mounted in said housing and movlil able in said firsthousing between a first position and a second position with respectthereto, said electric switch being positioned in said rst housing to beengaged by said movable member and actuated thereby when said movablestrip member is moved from said rst position to said second position, alamp housing member having an indicating face, `axially aligned couplingmembers mounted on said movable strip member and on said lamp housingmember and having a configuration for mutual engagement so as to supportsaid lamp housing member on said movable strip member for movementthereof with said movable strip member between said first and secondpositions of said movable strip member, and at least one electric socketmounted in one of said members for connection to the circuitry in saidfirst housing member for holding an electric annunciator lamp inposition to glow through the indicating 4face of said further memberupon the happening of the monitored condition.

8. The annunciator assembly defined in ciaim 7 and which includesresilient means mounted in said first housing member for biasing saidmovable member to said first position with respect to said first housingmember.

9. An indicating assembly including: a capsule-like housing containingelectric circuitry, a translucent lamp housing member having anindicating face with indicia thereon, a first electric socket supportedin said lamp housing member for holding an electric lamp therein in aposition to glow through the indicating face thereof, and a releasableelectric plug and socket combination respectively mounted on saidcapsuleelike housing and on said lamp housing member for removablysupporting said lamp housing member on said capsule-like housing andconnected to the circuitry in said capsule-like housing and to said rstelectric socket for establishing electric contact from said circuitry tosaid first electric socket.

l0. The assembly defined in claim 9 and which includes a first indexingmember mounted on said capsule-likc housing having a iiat planar portionextending essentially perpendicularly to the plane of said front edge ofsaid capsule-like housing at a predetermined angular orientation and asecond indexing member mounted on said translucent lamp housing memberhaving a flat planar portion extending essentially perpendicularly tothe rear face of said translucent lamp housing member at an angularorientation such that the flat planar portion of said second indexingmember is spaced and essentially parallel to the at planar portion ofsaid first indexing member when said translucent member is in place onsaid front edge of said capsule-like housing, said first and secondindexing members having a particular mating relationship so as toprevent other similar larnp housing members from being plugged intoengagement with said plug and socket combination.

References Cited in the file of this patent UNITED STATES PATENTS2,281,958 Snavely May 5, 1942 2,340,053 Grimes Jan. 25, 1944 2,769,974Hayes Nov. 6, 1956 2,797,407 Greenlee et al June 25, 1957 2,890,445Korry June 9, 1959 FOREIGN PATENTS 953,502 France May 23, 1949 630,333Great Britain Oct. 1l, 1949 UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION^ Fatemi; No, IO'MISO I' y I October 3L 1961 william C@Arraszmith i' It is hereby certified that error appears in ,the abovenumbered pat# entrequiring'correction and that the said Letters" Patentlshould read as corrected below.

Column l0, lin-e 354x, 1 after "h-ousingf: insert am having w.,

Signed and sealed this l0thola3 of April 1962.,

(SEAL) Attest:

ERNEST W. SWIDER e I DAVID L. LADD Attesting Officer Commissioner ofPatents 'E

